Tuesday, April 26, 2011

Hypertext Transfer Protocol (HTTP) is considered to be the fundamental protocol of the web. This simple request/response protocol is used for distributed, collaborative, hypermedia information systems. The web consumes a large portion of internet traffic.

With HTTP, a client makes a request for a resource to a server, and the server delivers messages with additional content such as images, style sheets and JavaScripts. HTTP dictates how these messages are displayed and transmitted, and how web servers and browsers should respond to various commands.

The developers of the HTTP protocol realised at an early stage that there was going to be rapid growth in web traffic. This continues to be the case. For example between 2000-2010, internet usage increased by more than 400%, much of which was accounted for by web traffic. With the anticipated insatiable demand for the web, developers added powerful caching primitives.

It is a demonstrable fact that the internet has changed individuals' expectations of the speed of content delivery. The same individuals who used to be content to wait a couple of days for a letter to be received now expect emails to be delivered within a matter of seconds. The same applies to web browsing. A slow-loading website is a recipe for online disaster even if the site is informative, well structured and organised. When it comes to interactive web usage, what really matters is median latency.

Web caches have become a vital mechanism for optimising the amount of data that is delivered in a given period of time. Good web caches also help to minimise latency, serving pages as quickly as possible. This helps to prevent the end user from becoming impatient having to wait for content to be delivered. Web caches optimise the data flow between client and server. They also help to converse bandwidth by caching frequently-delivered content. If you need to reduce server load and improve delivery speed of your content, it is definitely worth exploring the benefits offered by web cache software.

This type of software is primarily used by Internet Service Providers (ISPs), backbone providers, large intranets and enterprises. Web caches are very versatile, and are used in a number of different systems such as search engines, web proxies, and forward caches.

In this article, we feature the best open source software that caches web content, optimising and cleaning the network traffic.

To provide an insight into the open source software that is available, we have compiled a list of 6 of our favorite web cache software. Hopefully, there will be something of interest here for anyone who needs to reduce bandwidth usage, improve latency, and minimise server load.

So, let's explore the 6 web caches at hand. For each application we have compiled its own portal page, a full description with an in-depth analysis of its features, together with links to relevant resources and reviews.